ADAPTIVE IMMUNE SYSTEM

• Adaptive body defenses - the third line of defense against microorganism invasion
• Immune response - the immune system's response to a threat
• 3 Aspects of Adaptive Defense:

  • Antigen specific - recognizing and acting against foreign substances
  • Systemic - not restricting immunity to the initial infection site
  • Memory - recognizes and mounts a stronger attack on previously encountered pathogens
• 2 Arms of the Adaptive Defense System:

  • Humoral immunity - antibody-mediated immunity; mediated by B lymphocytes
  • Cellular immunity - cell-mediated immunity; mediated by T lymphocytes
• Antigens (Ag) - any substance capable of exciting the immune system and provoking an immune response
• Immunogens - antigens that are capable of stimulating an adaptive immune response
• Haptens (Incomplete antigens) - unable to cause an immune response by themselves, but can form antigenic determinants when combined with a larger molecule